Machine for making prints.



No. 708,989. Patented Sept. l6, I902.

R. A. BELL.

MACHINE FOR MAKING PRINTS.

(Application filed Feb. 18, 1902.)

(N 0 ll 0 d e l WITNESSES: y W a luvskoza t v. 4, 2 M a, 4 Q

ATTORNEY.

UNITED STATES PATENT OFFICE.

ROBERT ANGELO BELL, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO CHARLESA. RUTTER, OF PHILADELPHIA, PENNSYLVANIA.

SPECIFICATION forming part of Letters Patent No. 708,989, datedSeptember 16, 1902.

Application filed February 13, 1902. Serial No. 93,815- (No model.)

To all whom it may concern.-

Be it known that I, ROBERT ANGELO BELL, a citizen of the United States,and a resident of the city and county of Philadelphia, State ofPennsylvania, have invented certain new and useful Improvements inMachines for Making Prints, of which the following is a specification.

My invention relates to improvements in machines for making prints byelectric or other artificial light; and the object of my invention is tofurnish a means whereby the print will be of equal intensity throughout.One of the most common forms of machine for making prints by artificiallight consists of a glass cylinder or platen againstthe outside of whichthe tracing or negative is placed and outside of this the sensitivepaper,which, together with the negative or tracing, is held in placeagainst the cylinder by a curtain or blanket, which is drawn tightlyaround the cylinder. The light which fixes an image of the tracing ornegative upon the sensitive paper is gradually passed through thecylinder, its rays acting in the usual manner upon the sensitive paper.It has been found in practice that this machine is defective in that thelight is applied unequally at different parts of. the cylinder, the topof the cylinder, for instance, receiving light before the lamp enters itwhile the lamp is passing down past it and after the lamp has passed,while the lower part of the cylinder receives light only during theapproach and passage of the lamp, the result being a print of greaterintensity upon the top than on the bottom. To remedy this defect, Iplace both above and below the light screens, which cut off all raysabove and below, permitting only rays to pass between them. The screensare preferably of a size to just pass freely through the cylinder. Theyare preferably arranged as reflectors upon their sides next the light,so as not to absorb any of the rays, and one or both are easilydetachable from the lamp, so that access may be had to the latter fortrimming or adjustments. In the accompanying drawings, forming part ofthis specification, and in which si1nilar letters of reference indicatesimilar parts throughout both views, Figure 1 is a central sectionalelevation through the platen of a blue-printing machine, the lamp beingshown in side elevation; Fig. 2, a perspective view of the screens formasking the upper and lower rays from the light.

a is a glass platen; Z), a curtain or blanket for holding the negativeor print and the sensitive paper against the platen. c is anelectric-arc lamp; (Z, a cord from which lamp 0 is suspended; e, ahydraulic governor to which the cord dis attached and which serves tolower the lamp through the platen with a perfectlyregular motion. All ofthese parts were fully described in an application for patent filed byme in the United States Patent Office November 15, 1901, Serial No.82,462, and will not need detailed description at this time.

f g are screens carried by lamp 0, the screen fabove the light, thescreen 9 below it. These screens are of a diameter just small enough topass freely through cylinder or platen a and cut off all light above theupper and below the under one, causing all parts of the sensitive papertoreceive the same exposure from the lamp during its passage through thecylinder. The lower screen is preferably secured to the upper one byrods h 2', and the top of the upper screen is furnished with catches j,which are adapted to engage with catches 7c, carried by the lamp, inorder to removably secure the screws to the lamp, although any othersuitable and convenient means may be used for carrying the screens andfor attaching them to the lamp.

WVhile my light controlling screens are shown applied to aprinting-machine having a circular platen, it will be understood thatthe same principle may be applied to mao chines having flat platens andusing an artificial light.

By the term negative used in the claims I include whatever may be usedin producing the print desired. This may be a prop- 5 erly-termednegative or a drawing, tracing, &c.,according to circumstances and thewishes The paper or of the user of the apparatus.

other body upon which the print is to be made will be referred to in theclaims as a sensitized surface.

Having thus described my invention, I claim as new and desire to secureby Letters Patent 1. In an apparatus for making prints by artificiallight,the com bination of a glass platen, means for holding a negativeand a sensitized surface against the platen, an artificial light movableacross the platen, and means for protecting all portions of the platenexcept those opposite the light at any point in its travel from the raysof said light.

2. In an apparatus for making prints by artiiicial light,the combinationof a glass platen means for holding a negative and a sensitized surfaceagainst the platen, an artificial light movable across the platen, andscreens moving with said light and preventing the rays thereof fromstriking the platen except at points opposite the light.

3. In an apparatus for making prints by artificial light,the combinationof a glass platen, means for holding a negative and a sensitized surfaceagainst the platen, an artificial light movable vertically of theplaten, and two screens moving with and arranged, respectively, aboveand below said light, the screens tificial light,the combination of aglass platen,

means for holding a negative and a sensitized surface against theplaten, an artificial light movable vertically of the platen, a disk orscreen arranged above and moving with said light and acting to preventthe rays of said light from striking the platen above said disk, and asecond disk or screen, arranged below the light and detachably connectedto the first said screen, and acting to prevent the rays of said lightfrom striking the platen below said lower disk.

ROBERT ANGELO BELL.

Witnesses:

GEORGE W. SELTZER, CHARLES A. BUTTER.

